1. Technical Field
The present invention relates to machine vision and specifically the frame grabber or camera triggers used therein.
2. Background Information
Over the past several decades, the semiconductor has exponentially grown in use and popularity. The semiconductor has in effect revolutionized society by introducing computers, electronic advances, and generally revolutionizing many previously difficult, expensive and/or time consuming mechanical processes into simplistic and quick electronic processes. This boom in semiconductors has been fueled by an insatiable desire by business and individuals for computers and electronics, and more particularly, faster, more advanced computers and electronics whether it be on an assembly line, on test equipment in a lab, on the personal computer at one's desk, or in the home electronics and toys.
The manufacturers of semiconductors have made vast improvements in end product quality, speed and performance as well as in manufacturing process quality, speed and performance. However, there continues to be demand for faster, more reliable and higher performing semiconductors. To assist these demands, better inspection is necessary to increase yields.
To increase such yields, accurate and fast defect inspection is needed. One component of a typical defect inspection system is a machine vision frame grabber or camera triggering mechanism which is commonly provided as a feature of the motion controller. In such systems, a digital signal processor (DSP) with associated software is typically used to generate camera triggers. In these systems, trigger position updating (and in many cases the triggers themselves) are typically limited by the motion controller servo cycle and processing overhead. It is not uncommon for triggers to be delayed or missed entirely in demanding applications. This interferes with the accurate and fast inspection demands of the users of defect inspection systems.